Reconfigurable Resonant Converter with Wide Output Voltage Range for DC Fast Chargers

Current DC fast charging applications typically require a very wide dc output voltage range, such as 150 to 920 V, which strongly impacts performance, size and cost of typical dc-dc converters. This happens because the components need to be oversized in some sense due to higher current efforts at lower output voltage levels and higher voltage stresses at higher output voltages. This work presents a reconfigurable resonant LLC based dc-dc converter that improves this situation, without requiring rewiring, e.g, through relays. The main operating modes that enable this topology to operate in a wide voltage range are presented along with data that helps finding the most suitable operating regions.